Put Rainfall, Air Conditioning Back Into Trees, Scientists Say

Yellow cedar trees growing along Sheep Lake east of the Cascade crest in Washington State

This undated photo provided by the U.S. Forest Service shows yellow-cedar trees growing along Sheep Lake east of the Cascade crest in Washington State. A study documenting mortality of yellow cedar trees in Alaska and British Columbia concludes that the future is gloomy for the iconic species valued for its commercial and cultural values.

International climate and environment agreements have a flaw which may jeopardize attempts to curb global warming quickly: they do not highlight the role trees play in creating rainfall and cooling the earth’s surface, 22 scientists said on Tuesday.

Traditionally, international agreements have focused on how trees affect carbon levels in the atmosphere — living trees absorb carbon dioxide and deforestation releases carbon.

While that is important, it should not be the priority, the scientists said, while presenting results of their research at a virtual forestry symposium.

Heavy rain clouds move over the central business district in Bangkok.

Tree help with formation of clouds

Trees bring moisture to the air, and release chemicals that can lead to the formation of clouds, Meine van Noordwijk, chief science advisor at the World Agroforestry Center, told the Thomson Reuters Foundation.

Considering only their carbon storage “means we miss a huge opportunity,” van Noordwijk said, particularly as more erratic rainfall brings droughts and other problems around the world.

Countries are under pressure to curb emissions fast enough to keep global temperature rise to well below 2 degrees Celsius, as agreed under the 2015 Paris Agreement on climate change.

But viewing trees as carbon stores alone is not enough to mobilize governments and the public to ramp up forest protection or grow more trees as fast as they need to, they said.

Morning fog embraces the trees of the City Park of Budapest, Hungary, Friday, February 3, 2017. (Zoltan Balogh/MTI via AP)

Strollers walk during morning fog at the City Park of Budapest, Hungary, Feb. 3, 2017.

More shade needed in cities

The group of scientists called for a “significant revision” of national and regional strategies to reduce greenhouse gas emissions and adapt to climate change.

This includes planting more trees in cities, creating shade that naturally cools areas so people can spend less money and energy on air conditioning, the scientists said.

“The energy saving that can come from having the air conditioning of trees is gradually becoming better known,” van Noordwijk said, adding that some cities have begun recognizing the role trees can play.